"Boy enlistment was a traditional method of augmenting
recruitment. Regiments consisting entirely of boys had been
formed at an earlier date, but the last had disappeared in 1802.
Between 1859 and 1899 regulations specified that the number was
not to exceed 2 per cent of the establishment. Boys were taken on
from the age of fifteen and served an apprenticeship until they
reached the normal age of enlistment. During this time they were
taught one of two or three trades. Nearly three-quarters of the
boys recruited underwent training as musicians (i.e. drummers and
buglers), the remainder as tailors and shoemakers. On reaching
the minimum age for enlistment, boys formally joined the regiment
to which they were attached. What was new was the suggestion
inspired by the practices of the Royal Navy, of a comprehensive
training scheme. Borrowing directly from the navys
experience, many advocated that special training schools be set
up, and that the establishment of boys at the Royal Military
Asylum and the Royal Hibernian Military School be substantially
increased."

REFERENCE:

SKELLEY, A.R. The Victorian Army At Home: The Recruitment and
Terms and Conditions of the British Regular, 1859-1899.
McGill-Queens University Press, Montreal, 1977, pp. 240 and
243.